Broadly stated, the goal of this research is to obtain information which will illuminate the relationships between environmental variables and changes in children in the years between four and seven. More specifically, the goal is to explore experimentally the effects of specific treatment variables (program components) in a prekindergarten setting in order to determine their immediate and long-term impact on cognitive, motivational, perceptual, and achievement variables. The first phase of the research program focused on obtaining an adequate description of, and a comparison of the effects of, four intact preschool programs. This phase of the research has been completed. The major goal of the second phase is to explore the effects of experimental variation of combinations of specific techniques in preschool classrooms with curriculum materials and activities held constant across technique combinations.